1. Field Of The Invention
The present invention generally relates to leg devices for load carrying platforms, such as in portable staging and seating equipment. More particularly, the invention relates to an extendible leg device for use in supporting a portion of a platform assembly above a floor surface.
2. Discussion of the Prior Art
Platform assemblies are widely used in staging and seating equipment for auditoriums, gymnasiums, and event halls to accommodate performers or spectators. Depending on the intended use, a facility may require such equipment to be moved between use and storage positions on a repeated basis. To accommodate such repeated movement of the equipment, manufacturers may incorporate wheels, such as of the caster type. However, straight legs significantly out perform caster wheels with respect to platform stability and load carrying capacity. Hence, it is desirable to have an extendible leg device which permits transportation of a load carrying platform assembly on caster wheels while also offering the advantage of removing the load from the wheels, in whole or in part, so as to xe2x80x9cparkxe2x80x9d the equipment once it has reached its intended location for use or storage. Such parking enhances platform stability and load carrying capacity. Transportation and parking may be accomplished in at least two ways. The assembly could have attached wheels for floor engagement during transportation and then extendible legs having foot pads, where such legs extend to lift the assembly to remove at least a portion of the load from the wheels for parking. Alternatively, the assembly could have fixed legs for parking and extendible legs having wheels, where the legs having wheels extend to lift the assembly onto the wheels for use in transporting the assembly on a floor surface.
The extendible leg device of the present invention could be adapted for use with a platform assembly or the like in a side to side format or front to rear. Given that, in a position for use or storage, there may be obstructions, such as a side wall when using a side to side format, it is desirable to be able to access and control the raising or lowering of an extendible leg device from either end of the device.
It is further advantageous to conceal components of the extendible leg device within the structural components of the platform assembly, such as within commonly used tubular frame members, to protect such components from potential damage and to reduce undesirable pinch points.
It is also advantageous to achieve simple operation of such an extendible leg device, to enhance reliability and serviceability and so that it may be operated by unskilled individuals, with only a simple hand tool, such as a crank handle.
The present invention overcomes disadvantages of the prior art, while providing the above mentioned desirable features in an extendible leg device.
The purpose and advantages of the invention will be set forth in and apparent from the description and drawings that follow, as well as will be learned by practice of the invention.
The present invention is generally embodied in an extendible leg device for use with load carrying platforms, such as in staging or seating equipment. In a first aspect, the invention provides an extendible leg device having a plurality of substantially upright leg tubes, where each leg tube has a side wall, and a plurality of foot tubes, where each foot tube slidably engages a respective leg tube. The device further comprises an axle extending through the side wall of each leg tube and having a plurality of first links fixedly connected to the axle. A plurality of second links is provided with each second link pivotally connected at a first end to a first link and pivotally connected at a second end to a foot tube, wherein rotation of the axle causes slidable displacement of the foot tubes relative to the leg tubes.
In another aspect, the invention provides an extendible leg device having at least an extended position and a retracted position. The device comprises at least one substantially upright leg tube having a side wall and at least one foot tube slidably received in the at least one leg tube. An axle extends through the side wall of the leg tube and at least one first link is fixedly connected to the axle. At least one second link is pivotally connected at a first end to the at least one first link and pivotally connected at a second end to the at least one foot tube.
In still a further aspect, the present invention provides an extendible leg device having a plurality of substantially upright leg tubes, with each leg tube having a side wall. Also provided is a plurality of foot tubes, with each foot tube slidably engaging a respective leg tube. The device further comprises a substantially horizontal tube having a first end connected to a first upright leg tube and a second end connected to a second upright leg tube. An axle extends through the side wall of each leg tube and the substantially horizontal tube, and a plurality of first links is fixedly connected to the axle and disposed in the upright leg tubes. The device further comprises a plurality of second links, each second link being pivotally connected at a first end to a first link and pivotally connected at a second end to a foot tube, where rotation of the axle causes slidable displacement of the foot tubes relative to the leg tubes.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and provided for purposes of explanation only, and are not restrictive of the invention, as claimed. Further features and objects of the present invention will become more fully apparent in the following description of the preferred embodiment and from the appended claims.